KristallNacht wrote:based on principles of quantum physics, nothing can exist without being observed. If it's not being observed, it doesn't exist.

oh, that's such bullshit. Quantum physicists who actually support theories like that just want to feel comforted by the idea that human perception is some kind of a central and impactful element of nature.

Elements under the microscope change form whenever we look at them because we shoot photons at them, and the photons cause them to be distorted. The multi-verse theory is bullshit.

Well the question doesn't really take animals or other plants into account. It says "no one" not "nothing". I for one have never seen a single tree without some type of other life around it, so assuming that this is right, then something does observe it so yes it makes a sound. Just my thoughts.